Diseases of the Eye
A number of eye problems can result in the need for a corneal transplant, including:
Corneal Infections
Sometimes the cornea is damaged after a foreign object has penetrated the tissue, or bacteria or fungi from a contaminated contact lens can pass into the cornea. The ensuing painful inflammation and corneal infection is called keratitis. Keratitis can reduce visual clarity, produce discharges, and erode the cornea. Corneal infections can also lead to corneal scarring, which can impair vision and may require a corneal transplant.
As a general rule, the deeper the corneal infection, the more severe the symptoms and complications.
Fuchs' Corneal Dystrophy
Fuchs' dystrophy occurs when endothelial cells gradually deteriorate without any apparent reason. As more cells are lost, the endothelium becomes less efficient at pumping water out of the stroma. This causes the cornea to swell and distort vision. Eventually, the epithelium also takes on water, resulting in pain and severe visual impairment.
In one form or another, Fuchs’ dystrophy trademark deterioration of the cells covering the clear, outermost lens of the eye affects more than 4 percent of the population over 40. FCD is one of the leading reasons for corneal transplants.
Other Corneal Dystrophies
Corneal dystrophy is a condition in which one or more parts of the cornea lose their clarity due to a buildup of cloudy material. There are more than 20 corneal dystrophies that affect all parts of the cornea.
Corneal dystrophies are usually inherited, and they affect the right and left eyes equally. Most progress gradually. They are not caused by outside factors, such as injury or diet. Corneal dystrophies do not affect other parts of the body, nor are they related to diseases affecting other parts of the eye or body. They can occur in otherwise totally healthy people.
Herpes Zoster (Shingles)
This infection is produced by the same virus—called varicella-zoster—that causes chickenpox. In most people, after the initial outbreak of chickenpox, this virus remains inactive within the nerve cells of the central nervous system. But in some people, the virus will reactivate at another time in their lives. When this occurs, the virus travels down long nerve fibers and infects some part of the body.
Research has established two general risk factors for the disease: advanced age; and a weakened immune system. Studies show that people over age 80 have a five times greater chance of having shingles than adults between the ages of 20 and 40.
Corneal problems may arise months after the shingles are gone. For this reason, it is important that people who have had facial shingles schedule follow-up eye exams.
Keratoconus
This disorder--a progressive thinning of the cornea--is the most common corneal dystrophy in the U.S., affecting one in every 2000 Americans. It is more prevalent in teenagers and adults in their 20s. Keratoconus may also cause swelling and a sight-impairing scarring of the tissue.
In most cases, the cornea will stabilize after a few years without ever causing severe vision problems. But in about 10 to 20 percent of people with keratoconus, the cornea will eventually become too scarred or will not tolerate a contact lens. If either of these problems occurs, a corneal transplant may be needed.
Lattice Dystrophy
Lattice dystrophy describes an accumulation of abnormal protein fibers throughout the middle and anterior stroma which create a lattice effect. Over time, the lines grow opaque and involve more of the stroma, giving the cornea a cloudiness that may also reduce vision.
Although lattice dystrophy can occur at any time in life, the condition usually arises in children between the ages of two and seven. People with lattice dystrophy who require corneal transplant usually regain their sight, but the disease may also arise in the donor cornea in as little as three years.
Ocular Herpes
Herpes of the eye, or ocular herpes, is a recurrent viral infection that is caused by the herpes simplex virus. It is the most common infectious cause of corneal blindness in the U.S. Studies show that once people develop ocular herpes, there is up to a 50 percent chance of recurrence. The second flare-up can come weeks or even years later.
An estimated 400,000 Americans have had some form of ocular herpes. Each year, nearly 50,000 new and recurring cases are diagnosed in the United States, with the more serious stromal keratitis accounting for about 25 percent of cases.
How Transplants Help Those with Eye Disease
Corneal transplantation has restored sight to many who, a generation ago, would have been blinded permanently by corneal injury, infection, or inherited corneal disease or degeneration.
As people live longer than ever in the U.S., the need for transplantable corneas will continue to grow.
In the state of Wisconsin, 43% of the population is over the age of 40, and one in five people suffers from an eye disease. *
*Statistics from the Prevent Blindness report on Vision Impairment and Blindness in the U.S.